Tweak the module auto-import heuristics a bit

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@139887 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Lex/HeaderSearch.cpp b/lib/Lex/HeaderSearch.cpp
index 8a35080..ca641d4 100644
--- a/lib/Lex/HeaderSearch.cpp
+++ b/lib/Lex/HeaderSearch.cpp
@@ -289,7 +289,8 @@
 
   /// Determine whether this is the module we're building or not.
   bool AutomaticImport = SuggestedModule &&
-    (BuildingModule != StringRef(Filename.begin(), SlashPos));
+    (BuildingModule != StringRef(Filename.begin(), SlashPos)) &&
+    !Filename.substr(SlashPos + 1).startswith("..");
   
   FrameworkName.append(Filename.begin()+SlashPos+1, Filename.end());
   if (const FileEntry *FE = FileMgr.getFile(FrameworkName.str(),